Tobacco smoke filter for cigarettes, cigars, pipes and the like



July 2, 1968 L. LYNN 3,390,687

TOBACCO SMOKE FILTER FOR CIGARETTES, CIGARS, PIPES AND THE LIKE FiledJan. 23, 1967 [aw/ewes Ayn/7 INVENTOR.

United States Patent 3,390,687 TOBACCO SMOKE FILTER FOR CIGARETTES,CIGARS, PIPES AND THE LIKE Lawrence Lynn, Houston, Tex., assignor toRiviana Foods Inc., Houston, Tex. Continuation-impart of applicationSer. No. 427,285, Jan. 22, 1965. This application Jan. 23, 1967, Ser.No. 617,752

14 Claims. (Cl. 131266) Cross-reference to related applications Thisapplication is a continuation-in-part of application No. 427,285 filedJan. 22, 1965.

Background of the invention (1) Field of the inventi0n.-This inventionrelates to a new filtering material for cigarettes, cigars, pipes andthe like.

It has long been an object in the manufacture of smoking tobaccoproducts to produce filters for cigarettes, cigars and pipes and thelike to substantially reduce tars, resins and alkaloids, such asnicotine, which are inhaled during the smoking of tobacco. Many personswho smoke tobacco believe that the tars, resins, alkaloids and the likein tobacco smoke are injurious to health, and other consumers prefer touse a filter to remove these materials for reasons of personal taste,cleanliness, or esthetics.

(2) Description of the prior art.Heretofore, filtering materials such ascotton, cellulose acetate, fiberglass and the like have been employed tocollect and remove from the smoke certain condensible products containedtherein. Further, highly porous solid materials, such as activatedcarbons or charcoals, have been employed to remove such undesirableconstituents of the smoke. However, in the use of the aforementionedproducts as filtering materials, certain problems arise such asoff-flavor, loss of natural tobacco fiavor, low filtering efficiency,and high cost.

Summary of the invention A primary object of this invention is toprovide filtering material for use in filtering tobacco smoke whichcombines the advantages of low-cost, efiicient filtration, ease of draw,and minimum flavor interference.

Another object of this invention is to provide a filtering agent adaptedto be used in the manufacture of selfcontained filters for cigarettesand the like.

Other objects and advantages of the present invention will appear in thefollowing description, examples and appended claims.

The foregoing objects are achieved by this invention by providing,either alone or in combination with other filtering means, a precookedrice material in the form of discreet particles ranging in size frombetween about 100 and 850 microns in diameter as a filtering agent in atobacco smoke filter. The precooked rice material is produced bysubjecting whole grains or broken grains of white milled rice, brownrice, or parboiled rice to heat and moisture in amounts necessary forsubstantially complete cooking or gelatinization of the starch asmeasured organoleptically or chemically.

The rice is preferably cooked by immersion cooking or by a combinationof immersion cooking and steaming. Any suitable cooking means may beemployed; however, during at least a part of the cooking, an excess ofwater should be provided over that required for gclatinization. Theweight of water required for gelatinization of rice varies generallyfrom an amount as low as about double the Weight of the rice beingcooked to as high as about four times the Weight of the rice beingcooked. I presently prefer to employ a great deal more water than fourtimes the weight of the rice being cooked. The total cook- 3,39%,687Patented July 2, 1968 ing time required to gelatinize the rice withoutcausing the rupture of any substantial portion of the rice cells isbetween nine to eighteen minutes at about to 210 F. for raw rice andbetween eighteen to twenty-nine minutes at about 190 to 210 F. forparboiled rice and preferably about twenty-three minutes. If a two-stepcooking procedure is employed for raw rice, the immersion cooking shouldbe between nine to thirteen minutes at to 210 F. and the steaming shouldbe for a period of up to four minutes, preferably 0.5 to 3.5 minutes atpressures from 0 to 5 p.s.i.g. When the two-step procedure is employedfor parboiled rice, the immersion cooking should be between nine tofifteen minutes at 195 F. to 210 F. and the steaming should be from oneto five minutes, preferably two to four minutes at pressures from O to 5p.s.i.g.

It is presently preferred that loose starch be removed from the rice byat least one cold water washing and quenching step. If a two-stepprocedure of cooking is employed an intermediate cold water wash andquenching step is advantageous between the immersion cooking and thesteaming steps in order to facilitate the removal of loose starch.Although, as noted above, the steaming step is not necessary to producethe precooked rice utilized in the manufacture of the rice particles forthe present invention, it is advantageous as a means of completinggelatinization of the rice with little or no increase in moisturecontent, and with a minimum rupture of starch cells.

After the cooking or gelatinization of the rice is complete, it shouldbe dried by either a batch or continuous procedure. Freeze drying ordrying by hot air or other means may be used. For example, the moisturemay be effectively removed by a stream of heated air or a stream ofheated inert gas such as nitrogen. In order to obtain a porous driedrice particle, I prefer to dry the cooked rice by a stream of heated airat a temperature ranging from 230 to 270 F. for raw rice, and from 240to 300 F. for parboiled rice at a residence time of from nine to twentyminutes as necessary to obtain the desired final moisture content. Therice should be dried to a final moisture level below 14% and preferablybetween 6 and 12%.

After the cooked and washed rice particles of whole kernels or brokenkernels have been dried to the desired moisture content, the grains arethen subjected to conventional grinding or milling processes to producea granular size, ranging from between 100 to 850 microns in approximatediameter. The rice particles used in this invention are preferablyirregular shaped and of sufficient porosity to entrain and trapcombustion products of tobacco contained in the smoke normally inhaledduring the smoking of cigarettes, cigars, pipes and the like. Pre-cookedrice particles prepared as described herein will absorb water in amountsat least 4 times the weight of the rice particles when immersed in waterat 25 C. It is preferred that precooked rice particles used as a smokefiltering agent should have the capacity to absorb water in amounts atleast 4 times their own weight when immersed in an excess of water at 25C. for five minutes.

A suitable precooked rice product and process of manufacture thereof ismore fully disclosed in an application by Lawrence Lynn and Roy M.Anderson entitled Precooked Rice Flour and Method of PreparationThereof, application No. 427,486, filed Jan. 22, 1965. The riceparticles used in this invention are preferably irregularly shaped andof sufficient porosity to entrain and trap combustion products oftobacco contained in the smoke normally inhaled during the smoking ofcigarettes, cigars, pipes and the like.

In describing any filtering agent, the particles may be referred to asprecooked rice particles. By precooked rice I mean rice which has 'beengelatinized or ment 12. is disposed between the filter element and thecooked in contact with water and/or steam and dried tobacco-containingportion 15 of thecigarette. to a moisture content of less than 14% waterby weight. In FIG. 2, the filter element 10 is retained in positionPrecooked rice particles or precooked rice flour is between thetobacco-containing portion 15 of the cigarette, the granular riceproduced by conventional grinding or pervious closure 11 and wrapper 13.milling of such precooked rice. A number of cigarettes have been fittedwith filters The above described rice particles, ranging in size fromconstructed in accordance with this invention, utilizing 100 to 850microns in diameter, but preferably between the embodiment of FIG. 1where a filter measuring ap- 420 and 840 microns in diameter, are usedas a tobacco proximately inch in length was constructed with a smokefiltering element in the practice of my invention. filter sectionapproximately inch in length filled with particles of precooked rice.The cigarettes so constructed s t' zh ra s B'lef of e d wmg were testedand compared with the commercially available Turning 110W thfi drawings,1 is an aXOIlO- cigarettes containing a volume of activated charcoalequal metric projection of a cigarette with the filter wrapper to thevolume of precooked rice particles in the filters shown opened to eXpOsea filter construction illustrative 15 constructed according to thisinvention. A first series of of one embodiment of this invention. FIG. 2is an axono- 10 i tt were t t d i hi h th fil l t metric projection of acigarette with the filter wrapper ployed was composed of precooked riceparticles rangshown opened to expose the filter construction of an ingin size from approximately 259 microns to'approxalternative embodimentof this inv ntion. imately 420 microns with a bulk density ofapproximately .78 gm./cc. The filter elments were first weighed, and

Desmptlon of prefefled embodlments the 10 test cigarettes were smoked bythe application of In one preferred embodiment of my invention/thecontrolled suction to cause each cigarette to burn at a filter isprepared by forming a cylindrical tube about rate of approximately 1inch per minute. The test cigainch long, having a cross sectional 'areaidentical rettes, together with 10 control cigarettes containing an tothat of a standard cigarette, with about A to A; equal volume ofactivated charcoal as the filter clement, inch of the length of saidtube being filled with said were smokedat the same rate for a timesufiicient to conprecooked rice particles and further being held inplace sume approximately two inches of each cigarette and within thetube by closures of suitable pervious mathe filter removed and tested.terial at each end of the filter tube. The closure rna- Test data on the10 test cigarettes containing approxterial may be selected to provideadditional filtering imately 250 to 420 micron particles of precookedrice in cooperation with the precooked rice particles in a and thecontrol are tabulated below:

TABLE 1 Weight of Weight of Net Weight Filter Ele- Filter Ele- Gain-10Type of Filter ments Before merits After Filter Ele- Smoking (gnis)Smoking (gms) ments (gins) 10 Cigarettes 10 Cigarettes Precooked Rice,250420 Microns 2. 0976 2.1482 0. 0506 Charcoal Granule Filter 1. 2700 1.3076 0. 0376 multicomponent filter embodiment of my invention. TheAdditional tests were conducted for 10 cigarettes conabove describedtubular shaped filter may be attached taining particles of precookedrice ranging from approxto the cigarette by any conventional means.imately 420 microns to 840 microns. The results of these In analternative embodiment of the invention, the 5 tests are compared withthe data for 10 cigarettes confilter may be prepared by forming acylindrical tube with taining an equal volume of a commercial activatedchara pervious closure at only one end and with the precooked coalfilter, giving the following test results:

TABLE 2 Weight of Weight of Net Weight Filter Ele- Filter Ele- Gain10Type of Filter ments Before merits After Filter Ele- Smoking (gins)Smoking (gms) merits (gms.)

10 Cigarettes 10 Cigarettes Preeooked Rice, 420-840 Microns 1. 4364 1.4704 0. 0340 Charcoal Granule Filter 1. 2700 1. 3076 0.0376

rice material being disposed between such closure and the In anotheraspect of my invention, the embodiments tobacco of the cigarette. Itwill be apparent that any of FIGS. 1 and 2 may be regarded asniulticomponent desired size filter may be used and that it can be usedfilters in which conventional filtering means may be used a thefiltering element for pipe stems or cigar holders to serve both asadditional filtering elements and as s 1 as for Cigarettesy Suitablemeans y be closure means. It has been observed empirically that theprovided to retain the filter material. Moreover the preemciency ofabsorption f Such filt i means, f cooked rice Particles y be prenitfldedWith or Without ample, cellulose acetate, was enhanced by the presencethe incorporation of suitable bmdel' as by W 65 of the precooked rice asan adjacent filtering element. In trusion after molstemng to form aPorous disc of the the example illustrated by data in Table 2 above, the

diameter of a cigarette to provide a pervious filter material havingsufi'icient strength to be used without closure means. Further, theprecooked rice particles may be mixed or combined with other filtermaterials such as cellulose acetate, cotton batting, fiberglass,activated carbon or the lmately 2 grams f 10 clgarettee) of the totalfiltfir was Hir to f a Composite filt element enhanced approximately 16%over the amount absorbed In HQ 1 the filter element m Comprising a bodyf by the control. In the example illustrated in Table l, the

precooked rice particles is retained in position by pervious CCHUIOSQacetate Pomons of 1116 total p down: clcmcms H and 32 and Wrapper 3 (l g7; filter were found to absorb 86.5% more than the control celluloseacetate closures were the same as those used for the control. The netWeight gain (from 0.4101 to 0.4765 gram) for the cellulose acetateportions (approxas measured by net weight gain (from 0.4101 to 0.7652gram for cigarettes).

For maximum ease of drawing we presently prefer the particle range fromapproximately 420 to 840 microns with a bulk density ranging fromapproximately .58 to 0.80 gm./cc'., in which such bulk density dependsin part upon the processing of the rice during precooking and drying aswell as upon the size of the particles. However, as is readily apparentfrom the above data, improved filtering efficiency for a given volume offilter can be obtained by using a smaller particle size, such as the 250to 420 micron size particles which have a bulk density of approximately0.75 to 0.80 gm./ cc. 1

All of the above cigarettes were constructed with the filter elementdisposed between pervious filter elements comprising cellulose acetatematerial. Other suitable closure elements may be used, such as, forexample, cotton, synthetic fibers, fiberglass or treated syntheticfibers such as those discolsed in Touey et al., US. Patent No. 3,003,-504, dated Oct. 10, 1961.

Cigarettes employing the filter of this invention have been tested bysmokers for ease of draw, fiavor of smoke and the like. The filters ofthis invention were found essentially equal to the control filtercigarettes in case of draw and superior to charcoal filter cigarettes inthat there were no observed off-flavors typical of charcoal granulefilters. Further it was observed that there is a minimum of interferencewith the natural flavor of the cigarette as determined by comparingunfiltered controls with cigarettes containing the rice particlefilters.

The used filters of cooked rice particles were examined after smokingand found to be highly discolored, further indicating a large amount ofabsorption and adsorption of tobacco smoke condensates.

It will be obvious to persons skilled in the art that with minorvariations the precooked rice particle filters of this invention may beused in the construction of filters for cigars and pipes. Other changesand modifications of the invention can be made and insofar as suchvariations incorporate the true spirit of this invention, they areintended to be included within the scope of the appended claims.

I claim:

1. A tobacco smoke filter comprising a body of particles of precookedrice, the filter being characterized in that the particles of precookedrice are of a porous structure; a pervious retaining closure disposedadjacent one end of said body of precooked rice particles and said bodyof precooked rice particles being encircled about its circumference by awrapper.

2. A tobacco smoke filter, having disposed therein a filtering elementcomprising a body of particles of precooked rice flour, said particlesof rice flour being characterized by a porous structure.

3. The device of claim 2 in which said particles of precooked rice arefurther characterized by the major portion of the starch content of saidparticles being within unbroken starch cells.

4. The device of claim 2 in which said precooked particles of rice flourrange in particle sizes from approximately to 850 microns.

5. The device of claim 2 in which said particles of precooked rice flourrange in particle sizes from approximately 420 to 840 microns.

6. The device of claim 2 in which said rice flour ranges in bulk densityfrom approximately 0.40 to 0.80 gm./cc.

7. The device of claim 2 i n which said rice flour ranges in bulkdensity from approximately 0.58 to 0.80 gm./cc.

8. A tobacco smoke filter comprising a body of particles of precookedrice, the filter being characterized in that the particles of precookedrice are of a porous structure and the major portion of the starchcontent of said particles is contained in unbroken starch cells; saidbody of precooked rice particles being disposed between perviousretaining closures; and the body of precooked rice particles beingencircled about its circumference by a wrapper.

9. The tobacco smoke filter of claim 8, in which said particles ofprecooked rice have a moisture content below about 14%.

10. The tobacco smoke filter of claim 8, in which said particles ofprecooked rice have a moisture content between 6% and 12%.

11. A tobacco smoke filter, having disposed therein a filtering elementcomprising a body of discrete particles of precooked rice flour, saidparticles of rice fiour having a porous structure and further having amoisture content of below about 14%.

12. A tobacco smoke filter, having disposed therein a filtering elementcomprising a body of particles of precooked rice flour, said particlesof rice flour having a porous structure and further having a moisturecontent between 6% and 12%.

13. In a tobacco smoke filter, a multicomponen-t filter comprisingprecooked rice fiour particles as one filter element and fibers ofcellulose acetate as an additional filter element, said celluloseacetate fibers being adjacent said precooked rice flour particles.

14. The combination of claim 11 in which said precooked rice flourparticles are disposed between two cellulose acetate filtering elements.

References Cited UNITED STATES PATENTS 2,442,928 6/1948 MacMasters etal. 99 139 2,597,011 5/1952 MacMasters et a1. 12732 3,017,309 1/1962Crawford et a1. 131--266 x 3,251,365 5/1966 Keith et al. 131-265 XFOREIGN PATENTS 440,316 12/1935 Great Britain.

SAMUEL KOREN, Primary Examiner.

D. J. DONOHUE, Assistant Examiner.

2. A TOBACCO SMOKE FILTER, HAVING DISPOSED THEREIN A FILTERING ELEMENTCOMPRISING A BODY OF PARTICLES OF PRECOOKED RICE FLOUR, SAID PARTICLESOF RICE FLOUR BEING CHARACTERIZED BY A POROUS STRUCTURE.